This invention relates in general to musical instruments and deals more particularly with an improved method for making a sound board for a stringed musical instrument such as a guitar. The sound board for a high quality guitar is usually made from a relatively thin sheet of wood, as, for example, a sheet of solid spruce or fir. Such a sound board may, for example, be of graduated thickness, tapering from 0.140 inches near the neck end of the guitar to 0.110 inches at the end opposite the neck or may be of uniform thickness as, for example, 0.100 inches thick. It is customary to finish at least the outer surface of the sound board with a clear or transparent finishing material so that the natural grain of the wood is visible in the finished instrument. A high quality polyester resin, lacquer or urethane finishing material is frequently used for this purpose. While such sound boards generally provide desirable sound amplification, problems have been encountered with checking or cracking of the finish and in some instances cracking of the sound board when an instrument is subjected to extremes of temperature and humidity. This problem is particularly prevalent when availability of wood dictates that a lower grade of wood must be used. The present invention is particularly directed to this problem. However, it is a further aim of the invention to provide improved method for making a sound board for a quality instrument and which may be produced at lower cost than present sound boards of like quality.